The Protein Core support all Projects of this Program by providing synthetic peptides, determining partial amino acid sequences of proteins, identifying the nature and sites of post translational modifications, and generating antibodies. All of these services require highly specialized equipment and expertise which are best consolidated in a Core. The integrated nature of the Core assures cost efficiency and facilitates quality control. The integrated nature of the Core assures cost efficiency and facilitates quality control. Peptides, including sequences that include phosphoamino acids and other modifications, will be synthesized, purified and fully characterized by the Core. Protein characterization will be achieved by state-of-the-art procedures such as micro-scale chemical sequence analysis and mass spectrometry using both matrix assisted laser desorption and electrospray ionization techniques. Antibodies will be generated against synthetic peptides (including modified sequences) or against recombinant proteins. The proposals used assure that high titer specific antibodies will be obtained. Immuno-purification of antisera will be carried out when this is necessary. In addition, the Core Directors will provide expertise in the design of synthetic peptides, the planning of protein purification protocols, the application of search algorithms to identify sequences and other motifs in databases, and the prediction of antigenic sites in proteins.